Electromagnetic sounding apparatus.



adapted for automobiles, motor boats, electhe diaphragm, said means being located to tric railways, or' any other apparatus rethe front of the diaphragm, within the?,k

quiring an audible signal. A comparatively sound-amplifying element, and being accese' weak current is required to operate the desible for`adjustment through the open end of 25 vice, and the very high rate of vibration of the sound-amplifying element; the device the diaphragm produces a shrill note of including also an electromagnet rigidly supgreat'carrying power. ported to the rear of the diaphragm; an The 'casing section 5 is provided with a angular post secured to the magnet and probase 25 for securing the device in place, trudin through the dia hragm to over- 30 which may be done by means of bolts orx hang t e forward face o; the diaphragm; any other suitable fastening means 26. the said means consisting of an' adjusting What is claimed is: screw threaded into the post, in front of thc A device ofthe class described comprising diaphragm. a Haring sound-amplifying element, the In testimony that I claim the foregoing 35 inner sur ace of which is continuous and unas my own, I have hereto aiixed my signa? broken; a diaphragm lcated at the smaller ture in the presence of two witnesses. end of the sound-am Ii ying element; and a means for adjustingp the pulsations of the CHARLES W MCGONIGLE' diaphragm, which means is spaced from the Witnesses: sound-amplifying element and supported J. A. WESTERGREW, independently of the vibrating portion of H. B. HAGER. 4 

